The Age of Discovery of Elements Essay

880 Words 4 Pages
The Age of Discovery of Elements "The nineteenth century was the golden age for the discovery of elements. Scientists began to look for patterns of behaviour between elements."*1 Johann Döbereiner, a German chemist, was the first to attempt to categorise the elements. He used their atomic weights, which we now know as atomic masses.

In 1863, John Newlands, produced something that he called the 'Law of Octaves'. He used this to produce his own version of the periodic table, but Newlands came across some problems. "After about 20 elements his table became ragged,"*2 Newlands had left no gaps for undiscovered elements and even
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"Every element has it own characteristic set of lines. A new line (or lines) in a spectrum meant a new element."*6

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He called it Gallium, this new element had very similar properties to Mendeleev's predicted element 'eka-aluminium'; this therefore supported his idea of the Periodic table hugely.

Table 1, comparing Mendeleev's prediction with the properties of element 31, gallium. *7

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Gallium has some very unusual properties, some which suggest that it is a metal and some that imply it is a non-metal.

Its physical properties, a melting point of 29.78°C (which is almost UK room temperature) making it a liquid metal along with Mercury and Caesium. It also has an extremely high boiling point, 2403°C; together with its low boiling point gallium has the 'widest liquid range' of any element discovered so far. Gallium is also denser as a liquid than as a solid, as is water.

Word count: 190

Gallium's chemical properties include, dissolving in acid and alkalis, evolving hydrogen. Aluminium and

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